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Bulk thermoelectric (TE) nanocomposite materials have attracted considerable attention due to their great potential to exhibit higher dimensionless figure of merit ZT. Filled skutterudites of both n-type and p-type have already demonstrated their excellent high-temperature TE performance, good mechanical properties, and thermal stability. Herein, we extend this work to Yb-filled p-type skutterudite nanocomposites with in?situ precipitated FeSb2 nanoinclusions. Such a nanocomposite material can be easily synthesized by fine control of starting stoichiometry and the subsequent heat treatment process. By taking advantage of these naturally occurring FeSb2 nanoparticles, we achieve ZT max?=?0.74 in Yb0.6Fe2Co2Sb12/0.05FeSb2 at 780?K. We apply the method of four coefficients to calculate the density-of-states effective mass and the carrier scattering parameter. We find that a larger effective mass induced by the presence of nanoparticles is the origin of the enhanced Seebeck coefficient. 相似文献
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Bo Duan Pengcheng Zhai Shijie Ding Chenglong Xu Guodong Li Lisheng Liu Peng Li Qingjie Zhang 《Journal of Electronic Materials》2014,43(6):2115-2120
Nano-Co4Sb11.5Te0.5/Co4Sb11.5Te0.5 composites with different nanoparticle sizes and contents were obtained by ultrasonic dispersion followed by ball-milling and spark plasma sintering (SPS) processes. It was found that the nanoparticles obviously grew in size after SPS; most of them were larger than 200 nm in the 5%50 h and 10%50 h samples, while they were 100 nm to 200 nm in the 3%100 h and 5%100 h samples. The thermoelectric (TE) and mechanical properties of the nanocomposites with different sizes and contents were then characterized. Our results show that the TE properties were not noticeably affected, while the flexural strength and fracture toughness increased remarkably with the nanoparticle content, and the nanoparticle size had a notable effect on the mechanical properties of the nanocomposites; that is, the smaller the nanoparticles, the greater their reinforcing and toughening effects. 相似文献
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Characterization of powder-metallurgically manufactured (Bi x Sb1?x )2(Te y Se1?y )3 thermoelectric materials is presented. The manufacturing methods were spark plasma sintering (SPS) and hot isostatic pressing (HIP). x-Ray diffraction (XRD) and density measurements as well as transport characterization and scanning electron microscopy were performed on the materials. It is shown that both sintering techniques yield reasonable thermoelectric characteristics for p-type (x = 0.2, y = 1) as well as n-type (x = 0.95, y = 0.95) materials. Insight into the underlying reasons such as the scattering processes limiting the characteristics is gained by fitting experimental transport data using a theoretical model. The limitations and further optimization issues of our approach in thermoelectric material preparation are discussed. 相似文献
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Kwan-Ho Park Il-Ho Kim Soon-Mok Choi Won-Seon Seo Dong-Ik Cheong Hyung Kang 《Journal of Electronic Materials》2013,42(7):1377-1381
p-Type Yb z Fe4?x Co x Sb12 skutterudites were prepared by encapsulated melting and hot pressing, and the filling and doping (charge compensation) effects on the transport and thermoelectric properties were examined. The electrical conductivity of all specimens decreased slightly with increasing temperature, indicating that they were in a degenerate state due to high carrier concentrations of 1020 cm?3 to 1021 cm?3. The Hall and Seebeck coefficients exhibited positive signs, indicating that the majority carriers are holes (p-type). The Seebeck coefficient increased with increasing temperature to maximum values of 100 μV/K to 150 μV/K at 823 K. The electrical and thermal conductivities were reduced by substitution of Co for Fe, which was responsible for the decreased carrier concentration. Overall, the Yb-filled Fe-rich skutterudites showed better thermoelectric performance than the Yb-filled Co-rich skutterudites. 相似文献
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Kyu-Hyoung Lee Hyun-Sik Kim Sang-Il Kim Eun-Sung Lee Sang-Mock Lee Jong-Soo Rhyee Jae-Yong Jung Il-Ho Kim Yifeng Wang Kunihito Koumoto 《Journal of Electronic Materials》2012,41(6):1165-1169
Introducing nanoinclusions in thermoelectric (TE) materials is expected to lower the lattice thermal conductivity by intensifying the phonon scattering effect, thus enhancing their TE figure of merit ZT. We report a novel method of fabricating Bi0.5Sb1.5Te3 nanocomposite with nanoscale metal particles by using metal acetate precursor, which is low cost and facile to scale up for mass production. Ag and Cu particles of ??40?nm were successfully near-monodispersed at grain boundaries of Bi0.5Sb1.5Te3 matrix. The well-dispersed metal nanoparticles reduce the lattice thermal conductivity extensively, while enhancing the power factor. Consequently, ZT was enhanced by more than 25% near room temperature and by more than 300% at 520?K compared with a Bi0.5Sb1.5Te3 reference sample. The peak ZT of 1.35 was achieved at 400?K for 0.1?wt.% Cu-decorated Bi0.5Sb1.5Te3. 相似文献
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X. B. Zhao S. H. Yang Y. Q. Cao J. L. Mi Q. Zhang T. J. Zhu 《Journal of Electronic Materials》2009,38(7):1017-1024
Bulk thermoelectric materials are of interest for commercial application in both power generation and Peltier refrigeration.
Various synthesis approaches have been developed by our group for high performance bulk thermoelectric materials, such as
solvo- or hydrothermal synthesis for nanopowders, hot-pressing, and spark plasma sintering for nanostructured bulk materials,
and rapid solidification for metal silicides. In this article we report some of our recent results in the development of high
ZT thermoelectric materials, including Bi2Te3-Sb2Te3 nanocomposites and CoSb3 micro/nanocomposites prepared by a powder blending route, and GeTe-AgSbTe2 and Mg2Si-Mg2Sn nanocomposites prepared by an in situ route. The results show various possibilities for improved microstructures and therefore enhanced properties of bulk thermoelectric
materials through optimization of the preparation processing based on simple synthesis routes. A high ZT of approximately 1.5 has been obtained in both Bi2Te3-Sb2Te3 and GeTe-AgSbTe2 nanocomposites. Further ZT enhancement of the materials should be possible through the control of the nanopowder morphology during synthesis and the
hindering of␣grain growth during sintering, as well as through the optimization of composition and doping. 相似文献
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Han-Hui Xie Cui Yu Bin He Tie-Jun Zhu Xin-Bing Zhao 《Journal of Electronic Materials》2012,41(6):1826-1830
Half-Heulser thermoelectric materials ZrNi1?y Co y Sn (y?=?0, 0.02, 0.04, 0.08, 0.12) were prepared by a time-efficient levitation melting and spark plasma sintering procedure. X-ray diffraction analysis and electron probe microanalysis showed that single-phase half-Heusler compounds without compositional segregation have been obtained. The effects of Co doping on the electrical conductivity, Seebeck coefficient, and thermal conductivity of ZrNiSn-based half-Heusler alloys have been investigated from 300?K to 900?K. The Seebeck coefficient displayed a change from negative to positive values above nominal Co doping content of y?=?0.02, indicating a transition in the conduction behavior from n-type to p-type. The maximum dimensionless figure of merit ZT of undoped ZrNiSn sample reached 0.5 at 870?K. 相似文献
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用高温熔融-退火扩散法合成了富Co组成的方钴矿化合物CeyFexCo4-xSb12(y=0~0.42),并对化合物的结构和热电性能进行了研究.结果表明:化合物的晶格常数随Ce填充量的增加而线性增加.霍尔系数RH为正值,CeyFexCo4-xSb12化合物表现p型传导.载流子浓度和电导率随Ce填充量的增加而减少.Seebeck系数随Ce填充量的增加及温度的上升而增加.晶格热导率在Ce填充量约为0.29时达到最小值,说明在Sb组成的二十面体空洞中部分填充时,Ce的扰动对声子的散射作用最强.在725K时,组成为Ce0.29Fe1.41Co2.59Sb12.32化合物的最大无量纲热电性能指数达到0.65. 相似文献
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HeeJin Kim Mi-Kyung Han Chul-Hyun Yo Wooyoung Lee Sung-Jin Kim 《Journal of Electronic Materials》2012,41(12):3411-3416
A series of thermoelectric nanocomposite samples were prepared by integrating Bi2Se3 nanoparticles into a bulk Bi2Te3 matrix. Primarily, spherical Bi2Se3 nanoparticles with diameter of ~30 nm were synthesized by combining bismuth acetate with elemental Te in oleic acid solution. Bi2Te3-based nanocomposite samples were prepared by consolidating the appropriate quantity of Bi2Se3 nanoparticles with the starting elements (Bi and Te) using typical solid-state synthetic reactions. The microstructure and composition of the Bi2Te3-based nanocomposites, as well as the effects of the Bi2Se3 nanoparticles on their thermoelectric properties, are investigated. Transmission electron microscopy observation of the Bi2Te3-based nanocomposites reveals two types of interface between the constituent materials, i.e., coherent and incoherent, depending on the Bi2Se3 concentration. The Bi2Se3 nanoparticles in the Bi2Te3 matrix act as scattering centers for a wider range of phonon frequencies, thereby reducing the thermal conductivity. As a result, the maximum ZT value of 0.75 is obtained for the Bi2Te3 nanocomposite with 10 wt.% Bi2Se3 nanoparticles at room temperature. It is clear that the reduction in the thermal conductivity plays a central role in the enhancement of the ZT value. 相似文献
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Maria Ioannou Elli Symeou John Giapintzakis Theodora Kyratsi 《Journal of Electronic Materials》2014,43(10):3824-3830
Fabrication of nanocomposites by introduction of SiO2 metal oxide nanoparticles into a cobalt silicide thermoelectric matrix is studied. The CoSi matrix material was prepared through solid-state synthesis, and the nano-SiO2 metal oxide was introduced by mechanical grinding. The mixed powders were hot pressed to fabricate nanocomposites. The structural and morphological modifications were studied by powder x-ray diffraction analysis and scanning electron microscopy. The thermoelectric properties of the materials were followed through the Hall effect, Seebeck coefficient, and electrical and thermal conductivities in the temperature range from 300 K to 1000 K. 相似文献
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用高温熔融-退火扩散法合成了富Co组成的方钴矿化合物CeyFexCo4-xSb12(y=0~0.42),并对化合物的结构和热电性能进行了研究.结果表明:化合物的晶格常数随Ce填充量的增加而线性增加.霍尔系数RH为正值,CeyFexCo4-xSb12化合物表现p型传导.载流子浓度和电导率随Ce填充量的增加而减少.Seebeck系数随Ce填充量的增加及温度的上升而增加.晶格热导率在Ce填充量约为0.29时达到最小值,说明在Sb组成的二十面体空洞中部分填充时,Ce的扰动对声子的散射作用最强.在725K时,组成为Ce0.29Fe1.41Co2.59Sb12.32化合物的最大无量纲热电性能指数达到0.65. 相似文献
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Z. Chen Y. M. Han M. Zhou C. M. Song R. J. Huang Y. Zhou L. F. Li 《Journal of Electronic Materials》2014,43(4):1295-1301
Bi85Sb15?x Pb x (x = 0, 0.5, 1, 2, 3) alloys have been prepared by the mechanical alloying–spark plasma sintering (MA-SPS) method. X-ray diffraction and scanning electron microscopy were used to characterize the microstructure of the alloys. The effect of Pb content on the thermoelectric properties was investigated in the temperature range 77–300 K. The results showed that the electrical transport properties of the Bi–Sb alloys changed from n-type to p-type with substitution of Sb by Pb. The maximum power factor reached 1.6 × 10?3 W/mK2 at 190 K, a significant improvement on values reported elsewhere. This study demonstrated that high-performance p-type thermoelectric Bi–Sb materials can be obtained by spark plasma sintering. 相似文献
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Ekrem Güneş Bernadette Landschreiber David Hartung Matthias T. Elm Christian Rohner Peter J. Klar Sabine Schlecht 《Journal of Electronic Materials》2014,43(6):2127-2133
Bismuth nanotubes have been synthesized and successfully included in Bi1?x Sb x nanoalloys to form composite structures. The nanotubes were synthesized by transformation of a β-BiI precursor with n-BuLi solution leading to tubular bismuth structures. The Bi1?x Sb x nanoalloys were produced by ball milling. Three series of composite structures were synthesized by including different fractions (0 wt.%, 3 wt.%, 5 wt.%) of nanotubes in nanoalloys of different composition x. Investigation of thermoelectric and structural properties revealed a decrease of the thermal conductivity of up to 40% for the composites in comparison with alloys without nanotube inclusions. This effect can be attributed to enhanced phonon scattering. Seebeck coefficients and electrical conductivities were both slightly enhanced in the composite series with 3 wt.% nanotube inclusions, leading to enhancement of $$ ZT \ \left(ZT=\frac {(S^2 \sigma)}{\kappa}\,{ {T}}\right) $$ throughout the series compared with the nanoalloy series without nanotube inclusions. 相似文献
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Mikio Koyano Daichi Kito Kengo Sakai Tomoki Ariga 《Journal of Electronic Materials》2011,40(5):1078-1082
Application of a magnetic field greatly enhances the thermoelectric efficiency of bismuth-antimony (Bi-Sb) alloys. We synthesized
a hybrid of Bi-Sb alloy and magnetic nanoparticles, expecting improvement of the thermoelectric performance due to the magnetic
field generated by the nanoparticles. Powder x-ray diffraction and magnetic measurements of the synthesized hybrid Bi0.88Sb0.12(FeSb)0.05 sample indicated that the ferromagnetic FeSb nanoparticles, with a size of about 30 nm, were distributed in the main phase
of the Bi-Sb alloy. The FeSb nanoparticles act as soft ferromagnets in the diamagnetic host Bi-Sb alloy. The electrical resistivity
ρ of the host Bi0.88Sb0.12 sample decreased concomitantly with decreasing temperature, showing a shoulder at 80 K. In contrast, ρ for the hybrid sample was enhanced below 100 K because of carrier scattering by the nanoparticles. The temperature dependence
of the Seebeck coefficient S was also altered by the nanoparticle addition. In contrast, the addition of magnetic nanoparticles only slightly influenced
the thermal conductivity κ. These results indicate that the addition of magnetic nanoparticles to thermoelectric materials modulates the electronic
structures but does not influence the lattice system. 相似文献
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Jian Yu Wen-Yu Zhao Bing Lei Ding-Guo Tang Qing-Jie Zhang 《Journal of Electronic Materials》2013,42(7):1400-1405
A series of Ge-doped and (Ba,In) double-filled p-type skutterudite materials with nominal composition Ba0.3In0.2FeCo3Sb12?x Ge x (x = 0 to 0.4, Δx = 0.1) have been prepared by melting, quenching, annealing, and spark plasma sintering methods. The effects of Ge dopant on the phase composition, microstructure, and thermoelectric properties of these materials were investigated in this work. A single-phase skutterudite material was obtained in the samples with 0 < x ≤ 0.2, and trace Fe3Ge2 was detected in the samples with x ≥ 0.3. The electrical conductivity increased and Seebeck coefficient decreased with increasing x in the range of 0 to 0.2, while the inverse behaviors of electrical conductivity and Seebeck coefficient were observed in the samples with x ≥ 0.3. The variations of electrical conductivity and Seebeck coefficient are attributed to the significant increase in the carrier concentration in the x range of 0 to 0.2 and the intensive impact of Fe3Ge2 when x ≥ 0.3. The lattice thermal conductivity of all the Ge-doped samples was considerably reduced as compared with the undoped Ba0.3In0.2FeCo3Sb12 sample, and the lowest value of lattice thermal conductivity of the Ba0.3In0.2FeCo3Sb11.8Ge0.2 sample reached 1.0 W m?1 K?1 at 700 K. The highest ZT value of 0.54 was obtained at 800 K for the Ba0.3In0.2FeCo3Sb11.7Ge0.3 sample, increased by 10% as compared with that of Ba0.3In0.2FeCo3Sb12. 相似文献
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Kulbachinskii V. A. Kytin V. G. Zinoviev D. A. Maslov N. V. Singha P. Das S. Banerjee A. 《Semiconductors》2019,53(5):638-640
Semiconductors - Antimony-telluride-based nanocomposite samples containing different weight fractions of graphite (Sb2Te3 + x% graphite, where x = 0.0, 0.5, 1.0, and 2.5%) are synthesized and... 相似文献